Printing mechanisms, such as those used in desktop printers, may use one or more print cartridges, sometimes referred to as “pens,” which may shoot drops of liquid colorant, referred to generally herein as “ink,” onto a page. Each print cartridge may have a printhead formed with very small nozzles through which the ink drops are fired. To print an image, the printhead carriage carrying the printhead may be propelled back and forth across the page, firing drops of ink in a desired pattern as it moves. The particular ink ejection mechanism within the printhead may take on a variety of different forms known to those skilled in the art, such as those using piezo-electric or thermal printhead technology.
To clean and protect the printhead, a “service station” mechanism may be mounted within the printer chassis so the printhead can be moved over the station for maintenance. For storage, or during non-printing periods, the service stations may include a capping system which seals the printhead nozzles from contaminants and drying. To facilitate priming, some printers may have priming caps that are connected to a pumping unit to draw a vacuum on the printhead. During operation, partial occlusions or clogs in the printhead may be periodically cleared by firing a number of drops of ink through each of the nozzles in a clearing or purging process known as “spitting.” The waste ink may be collected at a spitting reservoir portion of the service station, known as a “spittoon.” After spitting, uncapping, or occasionally during printing, most service stations have a flexible wiper, or a more rigid spring-loaded wiper, that may wipe the printhead surface to remove ink residue, as well as any paper dust or other debris that has collected on the printhead. After wiping of the printhead by the wiper, the wiper may be scraped by a scraper to remove ink residue from the wiper.
The capping, spitting and wiping mechanisms of the service station may all be provided on a single service station sled for a variety of reasons, including reducing the space requirements of the service station. These multi-function service station sleds may not cap or uncap the printhead without also wiping the printhead and, in some cases, then scraping the wiper. Accordingly, a predetermined torque may be required in order to effect movement of the sled due to the multiple number of tasks that the sled may perform during each movement. Unnecessary wear and tear of the cap and/or the wiper may also occur because capping and/or wiping may not be required or desired during each movement of the sled. Moreover, the wiper, when it is scraped, may tend to flick ink from the wiper back onto the wiper or onto the printhead and the printhead carriage.